It is becoming increasingly popular to read in electronic form documents that have traditionally been available only in paper form, such as magazines, journals, such as trade journals and scientific journals, textbooks, photographic albums, newspapers and the like. However, many readers are reluctant to read these documents in electronic form because the electronic documents lack characteristics of paper documents to which the readers have become accustomed.
Techniques replicating characteristics of paper documents in electronic documents (also referred to herein as “virtual books”) is highly desirable. Virtual books may include a broad range of documents and include simulations of physical books such as magazines, journals, textbooks, photograph albums, newspapers or the like. Virtual books can be displayed by e.g., e-book systems, personal computers (PCs), personal digital assistants (PDAs), or the like.
Virtual book display systems, e.g., e-book systems, PCs, PDAs, or the like display virtual books in a two-dimensional (“2D”) manner or a three-dimensional (“3D”) manner. For example, B. Harrison describes several 2D-based e-book devices in “E-Books and the Future of Reading”, IEEE Computer Graphics and Applications, Vol. 10, No. 3, pages 32-39. It will be appreciated that, as used throughout the present disclosure, “three-dimensional” typically refers to implementation of a three-dimensional appearance of an object on a two-dimensional display, e.g., the display screen of a computer or the like.
Modern graphics systems provide ways to represent virtual books on a computer screen by creating a 3D appearance of a physical book. Displaying virtual books in a 3D manner provides a more realistic appearance of an actual physical book when compared to displaying virtual books in a 2D manner. 3D virtual books have many potential uses, such as, for example, the representation of historical manuscripts, the representation in electronic bookstores of books for sale, electronic book publishing, the basis of new forms of medical textbooks and other enhanced book formats, new forms of laboratory journals, and photograph albums.
A limitation on the ability of a virtual book to appear to a viewer as an actual physical book is at times limited to the appearance of the page while the page is being turned along with the page turning technique used by a virtual book display system. Realistic page turning can give readers and viewers the impression of reading or viewing an actual physical book. Since page turning is a dynamic animation that not only starts, but also finishes with the book in a static opened or closed position, how the static positions of the book are represented affects, to a large degree, how the book should be represented during the page turning animation, and vice versa.
There are various e-book systems for displaying electronic documents in a 3D manner. For example, U.S. Pat. No. 6,340,980 describes a special user interface device mimicking an actual physical book. When connected to a computer, this device works like any other user interface device such as a mouse. A software product, known as the Flip Browser®, has been developed by E-Book Systems Inc., and can be found at http://www.flipbrowser.com.
Additionally, U.S. Patent Application Publication No. 20020035697 describes systems and methods for distributing and viewing electronic documents. A software product, known as the Zinio Reader®, has been developed by Zinio Systems Inc., and can be found at http://www.zinio.com. Another system, the Turning the Pages® system is based on a multimedia authoring product called Macromedia. The Turning the Pages® system is jointly developed by the British Library and Armadillo Systems, and can be found at http://www.bl.uk/whatson/exhibitions/lindisfame/ttp.html. Although the above describe and/or display electronic documents in a 3D manner, the disclosures regarding the page turning feature for virtual books displayed in a three-dimensional manner are limited to little or no detail of how the page turning features are designed or implemented.
U.S. Pat. Nos. 5,847,709 and 5,838,326 describe another system, commercially known as the WebBook® developed by Xerox Corporation, for displaying electronic documents in a three-dimensional manner. Although the page turning animation of the WebBook® appears very similar to the page turning of an actual physical book, there are several drawbacks.
For example, an opened virtual book only models the top faces of the book, not the back side. Therefore, in a virtual environment where the back side or bottom faces, such as, for example, the front and back covers, of an opened virtual book are visible to the virtual camera, the virtual book may no longer resemble an actual physical book. A virtual camera is an imaginary device that may correspond to the reader's eye. The virtual camera displays the reader's view of the object, e.g. a virtual book, on the screen. Transitioning between a closed book and an opened book requires changing between the closed book representation and the opened book representation.
U.S. patent application Ser. No.10/739,175, the disclosure of which is incorporated herein by reference in its entirety, discloses a method for turning pages of a 3-dimensional electronic document having a predetermined length, a predetermined width and a predetermined thickness. The method may include, selecting a number of pages of the 3-dimensional document to be turned, each of the pages having a predetermined thickness; animating, relative to predetermined coordinates of a static base line, movement of a first 3-dimensional object, a second 3-dimensional object connected to the first 3-dimensional object at a first connection point, and a third 3-dimensional object connected to the second 3-dimensional object at a second connection point; and maintaining the first connection and the second connection while animating the movement of the first 3-dimensional object, the second 3-dimensional object and the third 3-dimensional object.
Additionally, WebBook® include a page ruffling technique that simulates the multiple concurrent turning of a set of pages of the WebBook®. The pages to be turned are represented by multiple turning pages blocks. However, although the page ruffling technique provides the capability to rapidly scan through a set of pages for information of interest, the ruffling technique requires that the textures of all of the pages being turned be displayed. The texture of the page includes the images shown on the page and may include both low and high resolution images. Therefore, in WebBook®, all of the page textures are pre-loaded and stored in the main memory. Pre-loading and storing all of the page textures in the main memory severely limits the scalability of the system and restricts the number of pages allowed in a virtual book. Furthermore, it is difficult to determine, even approximately, the amount of pages being turned during the page ruffling.